Centrifuge

ABSTRACT

A centrifuge including: a rotary chamber; a rotor installed in the rotary chamber; a driving unit configured to rotate the rotor; a chamber accommodating the rotary chamber, having a door, and configured to house gas therein; and a vacuum pump apparatus configured to exhaust the gas inside the chamber to an outside of the chamber, wherein the chamber is provided with a plurality of gas inlets and a plurality of valves configured to respectively open and close the gas inlets, and wherein all of the plurality of valves are configured to be opened when bringing an internal pressure of the chamber to atmospheric pressure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from Japanese Patent Application No.2013-110890 filed on May 27, 2013, the entire contents of which areincorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a centrifuge for decompressing achamber including a rotor rotary chamber, and particularly, relates to aconfiguration for decompressing a chamber and then returning an internalpressure of the chamber to atmospheric pressure.

BACKGROUND

By holding samples stored in tubes or the like by a rotor, disposing therotor in a rotor rotary chamber which is decompressed so as to preventtemperature from rising due to windage loss of the rotor, and rotatingthe rotor at a high speed by a driving device configured by an electricmotor or the like, a centrifuge centrifuges the samples held in therotor.

In general, in a so-called ultracentrifuge in which the rotation speedof the rotor exceeds 40,000 rpm, as disclosed in JP-A-2001-104826, inorder to suppress temperatures of the rotor and samples from rising dueto frictional heat attributable to windage loss of the rotor and air inthe rotor rotary chamber according to rotation of the rotor, theultracentrifuge includes a vacuum pump apparatus and a vacuum pressuredetecting means. The vacuum pump apparatus decompresses the rotor rotarychamber until the rotor rotary chamber becomes a high vacuum state. Thevacuum pressure detecting means includes a sensor and a sensor detectingcircuit and detects a vacuum pressure of the inside of the rotor rotarychamber.

The vacuum pump apparatus for decompressing the rotor rotary chamberfrom atmospheric pressure to the high vacuum state has a configurationin which an auxiliary vacuum pump for decompressing the rotor rotarychamber from atmospheric pressure to medium vacuum of about 13 Pa and anoil diffusion pump for decompressing the rotor rotary chamber from themedium vacuum to high vacuum of about 1 Pa are connected in series. Inorder to suppress the temperatures of the rotor and samples from risingdue to frictional heat attributable to windage loss of the rotor and airin the rotor rotary chamber according to rotation of the rotor, ingeneral, a so-called vacuum waiting operation for rotating the rotor ata predetermined low rotation speed, for example, at 5,000 rpm isperformed until the inside of the rotor rotary chamber is decompressedfrom atmospheric pressure to medium vacuum of, for example, about 13 Paby the vacuum pump apparatus. After the rotor rotary chamber reaches themedium vacuum, the rotor is accelerated to tens of thousands rpm tohundreds of thousands rpm, whereby centrifuging is performed.

Alternatively, in a case where a rise in the temperature of a sample dueto windage loss according to rotation of the rotor is desired to beminimized, in order to centrifuge the sample, a so-called vacuum startoperation in which the rotor is rotated for the first time after therotor rotary chamber reaches the medium vacuum of about 13 Pa isperformed.

In this kind of centrifuge having a vacuum pump apparatus as describedabove, the centrifuge includes a rotor rotary chamber that has a smoothsurface for minimizing windage loss according to rotation of a rotor,and a chamber (a vacuum container) that accommodates the rotor rotarychamber and evacuates the rotor rotary chamber and the periphery of therotor.

In the chamber, as disclosed in JP-A-H09-75782, there are provided adoor that is opened and closed to install or take out the rotor, adriving unit that rotates the rotor, a vacuum apparatus that evacuatesthe chamber, a pressure sensor that detects the vacuum pressure of thechamber, and an atmospheric-pressure air inlet that is connected to avalve which introduces air inside the chamber when bringing the internalpressure of the chamber to the atmospheric pressure and seals thechamber when evacuating the chamber.

In order to take out the rotor having finished centrifuging from therotor rotary chamber, wit is general to stop the vacuum apparatus whilerotation of the rotor is decelerated. After the rotation of the rotorstops, the valve connected to the atmospheric-pressure air inlet formedto the chamber is opened to introduce air into the chamber, and the dooris opened when the internal pressure of the chamber becomes atmosphericpressure so as to take out the rotor from the rotor rotary chamberprovided in the chamber.

SUMMARY

In this kind of centrifuge having the above described chamber, in orderto take out the rotor, an outlet having a large diameter (a diameter of50 cm) is necessary. Immediately after the rotor stops, a pressure ofabout 20,000 N is applied to a door provided to the outlet due toatmospheric pressure. Therefore, unless air is introduced into thechamber so as to completely return the inside of the chamber toatmospheric pressure, it is not possible to open the door.

Also, as the valve for opening or closing the atmospheric-pressure airinlet of the chamber, an electromagnetic valve is used. Theelectromagnetic valve is configured to be opened or closed by a switchprovided to an operation panel of the centrifuge. Also, for safetypurposes, the electromagnetic valve is configured so as not to be openedunless the rotor completely stops.

Also, as the electromagnetic valve, a general-purpose electromagneticvalve for pipes having inside diameters of ¼ inches (1 inch is 25.4 mm)to ⅜ inches is used. Even if an electromagnetic valve for large-diameterpipes having inside diameters of ⅜ inches is used to bring the internalpressure of the chamber to atmospheric pressure, in an example, about 40seconds are required. However, the time of 40 seconds is long for ananalyst wanting to take out the rotor including centrifuged samples fromthe centrifuge. Therefore, in order to improve operability, it isrequired to reduce the waiting time.

In order to solve these problems, it can be considered to increase theinside diameter of the atmospheric-pressure air inlet and the size of anorifice which is provided at a portion of the electromagnetic valvethrough which air passes, thereby reducing the total pipe resistance ofan atmospheric pressure air introduction portion, increasing air flow,and reducing the time necessary to bring the chamber to atmosphericpressure. However, in a case of increasing the pipe diameter of theatmospheric-pressure air inlet, the electromagnetic valve using theatmospheric-pressure air inlet also becomes bigger. Also, if a pipe islengthened in order to secure an installation space, the total piperesistance increases according to the length of the pipe, and thus thetime necessary to bring the internal pressure of the chamber toatmospheric pressure can not be reduced.

An object of the present invention is to provide a centrifuge capable ofovercoming the above described problems of the related art andincreasing the internal pressure of the chamber to atmospheric pressurein a short time after rotation of the rotor stops such that it ispossible to take out the rotor from the inside of the rotary chamberstoring the rotor in a short time.

According to an aspect of the present invention, there is provided acentrifuge including: a rotary chamber; a rotor installed in the rotarychamber; a driving unit configured to rotate the rotor; a chamberaccommodating the rotary chamber, having a door, and configured to housegas therein; and a vacuum pump apparatus configured to exhaust the gasinside the chamber to an outside of the chamber, wherein the chamber isprovided with a plurality of gas inlets and a plurality of valvesconfigured to respectively open and close the gas inlets, and whereinall of the plurality of valves are configured to be opened when bringingan internal pressure of the chamber to atmospheric pressure.

According to another aspect of the present invention, there is provideda centrifuge including: a rotary chamber; a rotor installed in therotary chamber; a driving unit configured to rotate the rotor; a chamberaccommodating the rotary chamber, having a door, and configured to housegas therein; and a vacuum pump apparatus configured to exhaust the gasinside the chamber to an outside of the chamber, wherein the chamber isprovided with a gas inlet and a valve configured to open and close thegas inlet, and wherein the gas inlet is configured to be supplied withcompressed gas.

Accordingly, after rotation of the rotor installed in the rotary chamberstops, it is possible to increase the internal pressure of the chamberaccommodating the rotary chamber to atmospheric pressure in a shorttime. As a result, it is possible to take out the rotor from the insideof the rotary chamber accommodating the rotor in a short time.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view illustrating the configuration of a centrifugeaccording to a first embodiment of the present invention;

FIG. 2 is an explanatory view illustrating examples of time variationsin the internal pressure of a chamber according to different structuresfor introducing air into the chamber; and

FIG. 3 is a view illustrating the configuration of a second embodimentof the present invention.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present invention will be described indetail with reference to the accompanying drawings. Components, members,processes, and the like shown in the drawings, which are identical orequivalent to each other, are denoted by the same reference symbol, andrepetitive explanation whereof will be omitted as necessary. Also, theembodiments do not limit the invention and are illustrative, and allfeatures to be described in the embodiments and combinations thereof arenot necessarily the essential features of the invention.

FIG. 1 shows an ultracentrifuge 100 as an example of a centrifugeaccording to a first embodiment of the present invention. In FIG. 1, theultracentrifuge 100 includes a rotor 1 for holding samples to centrifugethe samples, a driving unit (a motor) 2 for rotating the rotor 1 at ahigh speed, a rotor rotary chamber 3 in which the rotor 1 is installed(accommodated), a protector 4 for reducing influence on the entirecentrifuge in a case where the rotor 1 is broken down due to itsoperating life or the like, and a chamber (a vacuum container) 5. Thechamber 5 packs (accommodates) the rotor 1, the rotor rotary chamber 3,and the protector 4, and has a door 6 for taking out the rotor 1. In astate where the door 6 is closed, an opening of the chamber 5 isairtightly sealed.

Also, the ultracentrifuge 100 includes a vacuum pump apparatus in whichan auxiliary vacuum pump 7 and an oil diffusion vacuum pump 8 areconnected in series, in order to exhaust air in the chamber 5 to theoutside of the chamber 5 until the chamber 5 becomes a high vacuumstate. The auxiliary vacuum pump 7 is an oil rotation vacuum pump, a dryscroll vacuum pump, or the like for decompressing the rotor rotarychamber 3 to medium vacuum of, for example, about 20 Pa, and if an airexhausting operation of the oil diffusion pump starts in the mediumvacuum state, the rotor rotary chamber 3 is further decompressed. Theoil diffusion pump 8 decompresses the rotor rotary chamber 3 until therotor rotary chamber 3 becomes high vacuum, and the auxiliary vacuumpump 7 and the oil diffusion pump 8 are connected in series by a vacuumhose 9. The rotor rotary chamber 3 and the oil diffusion pump 8 areconnected by a vacuum pipe 10. In order to detect the temperature of theoil diffusion pump 8, a sensor 11 is provided, and the temperature ofthe oil diffusion pump 8 is detected by the sensor 11, whereby theoutput of the oil diffusion pump 8 is controlled by a control device 12of the centrifuge 100. The control device 12 performs control onrotation of the rotor 1, driving and temperature control on theauxiliary vacuum pump 7 and the oil diffusion pump 8, and temperaturecalculation based on a signal from the sensor 11, and so on. Anoperation unit (an input unit) 13 is installed for inputting operationconditions or issuing a start or stop command with respect to thecontrol device 12. Also, in order to detect the vacuum pressure of thechamber 5, a vacuum sensor 14 is provided, and on the basis of a signalfrom the vacuum sensor 14, the control device 12 calculates the degreeof vacuum of the rotary chamber 3, and performs vacuum waiting and highvacuum start.

To the chamber 5, there are provided an atmospheric-pressure air inlet15 for introducing air at atmospheric pressure so as to bring thechamber 5 to atmospheric pressure, and an electromagnetic valve 16 foropening or closing the atmospheric-pressure air inlet 15. If a commandfor opening and closing the atmospheric-pressure air inlet 15 is issuedfrom the operation unit 13, a signal is transmitted from the controldevice 12 to the electromagnetic valve 16 and the opening and closing isperformed.

The centrifuge 100 further includes an air compressor 17 for generatingcompressed air. The air compressor 17 includes a pressure container 17 athat stores the generated compressed air, and is turned on or off by thecontrol device 12. Specifically, if the pressure container 17 a reachesa predetermined pressure, the control device 12 performs control to stopthe operation of the air compressor 17. A compressed-air inlet 18 formedto the chamber 5 is connected to the pressure container 17 a of the aircompressor 17 through an electromagnetic valve 19, and according to asignal transmitted from the control device 12, the electromagnetic valve19 opens or closes the compressed-air inlet 18. In a case where theinside of the chamber 5 becomes atmospheric pressure or higher due tocompressed air supplied from the compressed-air inlet 18, air in thechamber 5 is exhausted from the atmospheric-pressure air inlet 15 to theoutside of the chamber 5 through the electromagnetic valve 16.Alternatively, a check valve 20, which seals the chamber 5 in a vacuumstate when the inside of the chamber becomes a decompressed state or avacuum state and exhausts the air inside the chamber 5 when the internalpressure of the chamber 5 becomes the atmospheric pressure or higher, isprovided to the chamber 5.

The operation of the first embodiment having the configuration of FIG. 1will be described with reference to FIG. 2. FIG. 2 shows time variationsin the internal pressure of the chamber 5 in a case where air isintroduced from the atmospheric-pressure air inlet 15 and thecompressed-air inlet 18 from a state where the inside of the chamber 5was in high vacuum.

The rotor 1 containing samples, which has been rotated at apredetermined rotation speed in the chamber 5 evacuated to high vacuumby the oil diffusion pump 8 and the auxiliary vacuum pump 7 for apredetermined time, is decelerated until the rotor 1 stops. Then, when arotation sensor provided to the driving unit 2 detects the stop, whilethe control device 12 stops the oil diffusion pump 8 and the auxiliaryvacuum pump 7, thereby stopping evacuating, a display representing thatit is possible to introduce air into the chamber 5 is displayed on theoperation unit 13.

Meanwhile, while the chamber 5 is in high vacuum, the electromagneticvalve 19 for closing the compressed-air inlet 18 is closed and the aircompressor 17 is operated such that compressed air of about 0.7 MPa isstored in the pressure container 17 a (for example, a container with acapacity of 3.5 L) provided to the air compressor 17. Then, after adisplay representing that it is possible to introduce air into thechamber 5 is displayed on the operation unit 13 as described above, whena command for opening a door 6 is input from the operation unit 13, atthe same time as the electromagnetic valve 16 connected to theatmospheric-pressure air inlet 15 is opened, the electromagnetic valve18 intercepting a flow between the pressure container 17 a of the aircompressor 17 and the compressed-air inlet 18 is opened, whereby air inatmospheric pressure and compressed air are introduced into the chamber5 at the same time. Variation in the internal pressure of the chamber 5in this case is shown by a curve 50 c of FIG. 1, and only a time(T₁-T_(B)) is required to bring the internal pressure of the chamberfrom high vacuum (a pressure of P_(U)) to atmospheric pressure (apressure of P_(A)) at which it is possible to open the door 6. Here, thetime T_(B) represents a time at which air starts to be introduced intothe chamber 5.

For comparison with the case of the first embodiment, variation in theinternal pressure of the chamber 5 until the chamber 5 reaches thepressure of P_(A) in a case of opening only the electromagnetic valve 16connected to the atmospheric-pressure air inlet 15 so as to introduceair into the chamber 5 according to the related art is shown by a curve50 a of FIG. 2. The curve 50 a shows that a time (T₃-T_(B)) is requiredto bring the internal pressure of the chamber from high vacuum (thepressure of P_(U)) to atmospheric pressure (the pressure of P_(A)). Ascan be seen from the comparison between the curve 50 a and curve 50 c ofFIG. 2, in the first embodiment, the chamber reaches the pressure atwhich it is possible to open the door 6 in a shorter time of (T₁-T_(B))(which is about one third of (T₃-T_(B))) than that in the related art.

According to the present embodiment, it is possible to achieve thefollowing effects.

(1) In introducing air into the chamber 5 when opening the door 6, aircompressed by the air compressor 17 is used. That is, it is possible toperform air introduction using high-pressured compressed air. Therefore,it is possible to bring the internal pressure of the chamber 5 to theatmospheric pressure in a shorter time as compared to general airintroduction only from one atmospheric-pressure air inlet 15 using adifference in air pressure between the inside and outside of the chamber5 according to the related art. Therefore, it is possible to reduce awaiting time for opening the door 6.

(2) Air introduction into the chamber 5 uses not only introduction ofair compressed by the air compressor 17 but also introduction of air inatmospheric pressure using a difference in air pressure between theinside and outside of the chamber 5. Therefore, it is possible to bringthe internal pressure of the chamber 5 to the atmospheric pressure in afurther shorter time.

(3) To the chamber 5, the atmospheric-pressure air inlet 15 is formedseparately from the compressed-air inlet 18. Therefore, even in a casewhere compressed air is excessively supplied into the chamber 5 suchthat the internal pressure of the chamber 5 reaches the atmosphericpressure or higher, it is possible to exhaust air in the chamber 5 fromthe atmospheric-pressure air inlet 15, thereby preventing an abnormalrise in the internal pressure of the chamber 5.

(4) To the chamber 5, the check valve 20 is provided. Therefore, in acase where compressed air is excessively supplied into the chamber 5such that the internal pressure of the chamber 5 reaches the atmosphericpressure or higher, it is possible to prevent an abnormal rise in theinternal pressure of the chamber 5, and when the electromagnetic valve16 for the atmospheric-pressure air inlet 15 does not operate, the checkvalve 20 acts as an alternative safety valve, thereby capable ofpreventing an abnormal rise in the internal pressure of the chamber 5.As a result, it is possible to further improve safety.

FIG. 3 shows a second embodiment of the present invention. In this case,instead of the compressed-air inlet 18 and the electromagnetic valve 19for opening and closing the compressed-air inlet 18 of FIG. 1, anotheratmospheric-pressure air inlet 15 and another electromagnetic valve 16for opening and closing the another atmospheric-pressure air inlet 15are provided to the chamber 5.

In order to open the door 6 of the chamber 5, the twoatmospheric-pressure air inlets 15 are opened so as to introduce air inatmospheric pressure into the chamber 5. Variation in the internalpressure of the chamber 5 in this case is shown by a curve 50 b of FIG.2. In the curve 50 b, a time (T₂-T_(B)) is required to bring theinternal pressure of the chamber from high vacuum (the pressure ofP_(U)) to atmospheric pressure (the pressure of P_(A)). Therefore, ascan be seen from FIG. 2, the required time is sufficiently reduced ascompared to the time of (T₃-T_(B)) in the case where oneatmospheric-pressure air inlet 15 is open.

Although the invention has been described by reference to theembodiments, it can be understood by those skilled in the art that avariety of modifications can be applied to the components and processesof the embodiments without departing from the scope of the followingclaims. Hereinafter, modifications will be described.

In each embodiment, three or more inlets for introducing compressed airor air in atmospheric pressure may be formed to the chamber 5.

Further, as a gas to be introduced into the chamber 5, air has beenexemplified. However, it is possible to use gases other than air inaccordance to the purposes.

The first embodiment has a configuration including the air compressorthat generates compressed air and stores the compressed air in thepressure container. However, the centrifuge may be configured to includean exchangeable pressure container which stores compressed gas inadvance such that compressed gas is supplied from the pressure containerinto the chamber 5.

The present invention provides illustrative, non-limiting aspects asfollows:

(1) In a first aspect, there is provided a centrifuge including: arotary chamber; a rotor installed in the rotary chamber; a driving unitconfigured to rotate the rotor; a chamber accommodating the rotarychamber, having a door, and configured to house gas therein; and avacuum pump apparatus configured to exhaust the gas inside the chamberto an outside of the chamber, wherein the chamber is provided with aplurality of gas inlets and a plurality of valves configured torespectively open and close the gas inlets, and wherein all of theplurality of valves are configured to be opened when bringing aninternal pressure of the chamber to atmospheric pressure.

(2) In a second aspect, there is provided the centrifuge according tothe first aspect, wherein any one of the gas inlets is configured to besupplied with compressed gas, and wherein the other gas inlet isconfigured to be supplied with gas in atmospheric pressure.

(3) In a third aspect, there is provided the centrifuge according to thesecond aspect, further comprising an air compressor including a pressurecontainer, wherein the compressed gas, which is compressed air, issupplied from the pressure container to the gas inlet.

(4) In a fourth aspect, there is provided the centrifuge according toany one of the first to third aspects, wherein the chamber is providedwith a check valve configured to seal the chamber when the internalpressure of the chamber becomes a decompressed state and exhaust gasinside the chamber when the internal pressure of the chamber becomeshigher than atmospheric pressure.

(5) In a fifth aspect, there is provided a centrifuge including: arotary chamber; a rotor installed in the rotary chamber; a driving unitconfigured to rotate the rotor; a chamber accommodating the rotarychamber, having a door, and configured to house gas therein; and avacuum pump apparatus configured to exhaust the gas inside the chamberto an outside of the chamber, wherein the chamber is provided with a gasinlet and a valve configured to open and close the gas inlet, andwherein the gas inlet is configured to be supplied with compressed gas.

(6) In a sixth aspect, there is provided the centrifuge according to thefifth aspect, further comprising an air compressor including a pressurecontainer, wherein the compressed gas, which is compressed air, issupplied from the pressure container to the gas inlet.

(7) In a seventh aspect, there is provided the centrifuge according tothe fifth or sixth aspect, wherein the chamber is provided with a checkvalve configured to seal the chamber when an internal pressure of thechamber becomes a decompressed state and exhaust gas inside the chamberwhen the internal pressure of the chamber becomes higher thanatmospheric pressure.

Also, arbitrary combinations of the above described components andmodifications obtained by conversion of the present invention intomethods and systems are also valid as embodiments of the presentinvention.

What is claimed is:
 1. A centrifuge comprising: a rotary chamber; arotor installed in the rotary chamber; a driving unit configured torotate the rotor; a chamber accommodating the rotary chamber, having adoor, and configured to house gas therein; and a vacuum pump apparatusconfigured to exhaust the gas inside the chamber to an outside of thechamber, wherein the chamber is provided with a plurality of gas inletsand a plurality of valves configured to respectively open and close thegas inlets, and wherein all of the plurality of valves are configured tobe opened when bringing an internal pressure of the chamber toatmospheric pressure.
 2. The centrifuge according to claim 1, whereinany one of the gas inlets is configured to be supplied with compressedgas, and wherein the other gas inlet is configured to be supplied withgas in atmospheric pressure.
 3. The centrifuge according to claim 2,further comprising an air compressor including a pressure container,wherein the compressed gas, which is compressed air, is supplied fromthe pressure container to the gas inlet.
 4. The centrifuge according toclaim 1, wherein the chamber is provided with a check valve configuredto seal the chamber when the internal pressure of the chamber becomes adecompressed state and exhaust gas inside the chamber when the internalpressure of the chamber becomes higher than atmospheric pressure.
 5. Acentrifuge comprising: a rotary chamber; a rotor installed in the rotarychamber; a driving unit configured to rotate the rotor; a chamberaccommodating the rotary chamber, having a door, and configured to housegas therein; and a vacuum pump apparatus configured to exhaust the gasinside the chamber to an outside of the chamber, wherein the chamber isprovided with a gas inlet and a valve configured to open and close thegas inlet, and wherein the gas inlet is configured to be supplied withcompressed gas.
 6. The centrifuge according to claim 5, furthercomprising an air compressor including a pressure container, wherein thecompressed gas, which is compressed air, is supplied from the pressurecontainer to the gas inlet.
 7. The centrifuge according to claim 5,wherein the chamber is provided with a check valve configured to sealthe chamber when an internal pressure of the chamber becomes adecompressed state and exhaust gas inside the chamber when the internalpressure of the chamber becomes higher than atmospheric pressure.